Percent Ms. Crusenberry 9-2013

Vocabulary Percent % - part per one hundred Rate – percent Base – the amount you are taking a part of percent of Percentage – result obtained by multiplying a number by a percent

Changing Percents to Decimals and Fractions Remember your place value decimal chart 24% = .24 or 24/100 6% = .06 or 6/100 Simplify - 6/25 3/50

How to Change a Percent to a Decimal To change a percent to a decimal, move the imaginary decimal to places to the left and drop the percent sign Ex. 1 3. % **there is always an imaginary decimal behind every whole number. Move it two places to the left and drop the percent sign. So, 13.% = .13

What if???? You had just 5%? In order to move the imaginary decimal two places to the left, you will have to add a zero (0) in front of the 5. 0 5 .% = .05

Change the following to both a decimal and a fraction. Practice Change the following to both a decimal and a fraction. 13% 7% 68% 120%

Answers .13 13/100 .7 7/10 .68 68/100 17/25 1.20 1 20/100 1 1/5

Renaming Fractions and Decimals as Percents To rename a fraction as a decimal, divide the numerator by the denominator .75 Ex. ¾ = 4 3.00 -2 8 20 - 20 0 Now to make it a %, move the decimal two places to the right. This equals 75%

Practice Fraction Decimal Percent 5/9 1/15 5/8 1/2 2/3 6/7 3/16

Fraction Decimal Percent 5/9 .56 56% 1/15 .07 7% 5/8 .63 63% 1/2 .5 50% 2/3 .67 67% 6/7 .86 86% 3/16 .19 19%

Vocabulary Rate – percent Base – the amount you are taking a part or percent of Percentage – result obtained by multiplying a number by a percent 20% of 80 is 16 rate base percentage

Finding the Is There are two ways to do this. First is the is/of = %/100 formula Second is to change the percent to a decimal and then multiply it by the of Ex. 28% of 62 is what number .28 x 62 = 17.36 the formula is on the next slide….

Formula is = % of 100 x = 3 45 100 100x = 135 100 100 x = 1.35

Use whichever way you are comfortable with!! Practice Use whichever way you are comfortable with!! 22% of 36 is ____? 7% of 48 is _____? 3.2% of 15 is _____? 36% of 36 is _____?

Answers 7.92 3.36 .48 12.96

Finding the Of There are two ways to do this. First is the is/of = %/100 formula Second is to change the percent to a decimal and then divide the is by the decimal Ex. 25% of what number is 12? 12 ÷ .25 = 48 the formula is on the next slide….

Formula is = % of 100 12 = 25 x 100 1200 = 25x 25 25 x = 48

Use whichever way you are comfortable with!! Practice Use whichever way you are comfortable with!! 22% of _____ is 17.6 45% of ____ is 80.55 5% of _____is 92. 1.3% of _____ is 60.

Answers 80 179 1840 4615.38

Finding the % There are two ways to do this. First is the is/of = %/100 formula Second is to divide the is by the of Ex. _____ of 17 is 1.02? 1.02 ÷ 17 = .06 = 6% the formula is on the next slide….

Formula is = % of 100 1.02 = x 17 100 102 = 17x 17 17 x = 6 = .06 = 6%

Practice Use whichever way you are comfortable with!! _____ % of 18 is 2.7 _____% of 45 is 9 _____ % of 200 is 120 _____ % of 70 is 10.5

Answers 15% 20% 6%

Problem Solving You receive 7/8 of the votes cast. What percent of the votes do you receive? You correctly answer 32 problems out of 35 problems on a test. What percent of the problems does he get correct? An advertisement claims that seven out of ten doctors recommend Brand A aspirin. What percent of the doctors recommend the aspirin?

Continued…. A test has 50 questions. You get 90% correct. How many questions did you get correct? The team plays 60 games. They win 30%. How many do they win? 35 students are in class. 60% are girls. How many are girls? How many are boys?

Continued… 75% of the buses have arrived. 48 have arrived. How many buses are there in all? 80% of the students vote. 48 students vote. How many students are there in all? You lose 32% of your beads. You lost 24 beads. How many beads did you have to begin with?

Continued… 40 students are in the class. 18 students go on the field trip. What percent go on the field trip? The total distance is 52 miles. Sue drives 13 miles. What percent of the distance does she drive? Gary attempts 84 shots. He makes 63. What percent of the shots does he make?

Answers 7 ÷ 8 = 88% 32 ÷ 35 = 91% 7 ÷ 10 = 70% .90 x 50 = 45 .30 x 60 = 18 .60 x 35 = 21, 14 are boys 48 ÷ .75 = 64 48 ÷ .80 = 60 24 ÷ .32 = 75 18 ÷ 40 = 45% 13 ÷ 52 = 25% 63 ÷ 84 = 75%